PAOK Thessaloniki said they had been subject to a police operation "reminiscent of a terrorist raid" before they slipped to a 1-0 defeat to bitter Greek Super League rivals Olympiakos on Sunday.

Despite fears of violent clashes between fans at the high-security fixture, the game passed off peacefully.

Hundreds of police, a security drone watching from above and a net around the Toumba Stadium pitch, as protection against thrown debris and other objects, kept things surprisingly quiet.

A huge police operation earlier in the day, in and around the stadium, failed to find any dangerous objects which may have been used by hooligans.

That intense security sweep angered PAOK.

"PAOK made every effort to ensure the smooth running of today's showdown," PAOK said in a statement.

"This attempt was made to torpedo the match, a few hours before the start of the derby with the unprecedented presence of the police force early in the morning reminiscent of a terrorist raid."

PAOK defender Dimitris Giannoulis scored an own goal in the 49th minute with a reply from the home side's Cape Verdean defender Fernando Varela ruled out after a VAR review.

The win by Olympiakos kept them in first place in the title race after 25 matches with 63 points, five more than second place PAOK.